JP2001150720A - Method for manufacturing optical printer head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for forming an optical printer head which can obtain clear images corresponding to image data. SOLUTION: The optical printer head is manufactured by a process in which a light-emitting element array chip 4 with a plurality of light-emitting elements 5 and a plurality of electrode terminals 6 formed to an upper face is loaded on a circuit board 1 having a plurality of circuit wiring 3 provided thereto, and the circuit wiring 3 and the corresponding electrode terminal 6 are connected by a bonding wire 7; a process in which surfaces of the light-emitting elements 5 are coated with a hydrophilic resin 9 and then the bonding wire 7 is coated with a hydrophobic resin 8 of a reflectance of not larger than 10%; and a process in which the hydrophilic resin 9 is dissolved in water and removed, thereby exposing the light-emitting elements 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an optical printer head incorporated as an exposure means for an electrophotographic printer or the like.

[0002]

2. Description of the Related Art Conventionally, an optical printer head incorporated as an exposure means of an electrophotographic printer or the like is provided on a circuit board 11 on which a plurality of circuit wirings 12 are attached, as shown in FIG. A light emitting element array chip 13 having a large number of light emitting elements 14 and electrode terminals 15 is mounted thereon, and the circuit wiring 12 and the electrode terminals 15 corresponding to the wirings 12 are electrically connected by bonding wires 16. The power is supplied to the light emitting element 14 through the circuit wiring 12 and the electrode terminal 15 so that the light emitting element 14 selectively emits light individually based on image data, and the emitted light is not shown. It functions as an optical printer head by irradiating and forming an image on a photoconductor via a lens and forming a predetermined latent image on the photoconductor.

Incidentally, the latent image formed on the photosensitive member is thereafter
A toner image is formed through a development process, and a predetermined image is recorded on the recording paper by transferring and fixing the toner image on the recording paper.

[0004]

However, in the above-described conventional optical printer head, the bonding wire 16 for connecting the electrode terminal 15 on the upper surface of the light emitting element array chip to the circuit wiring 12 is usually made of gold (Au) or gold. When the optical printer head is used, the light emitting element 14 is made of a glossy metal such as aluminum (Al).
Is emitted, a part of the emitted light hits the bonding wire 16 and causes irregular reflection. In this case, since the photosensitive member is irradiated with unnecessary light, an accurate latent image corresponding to the image data cannot be formed, and the image quality is remarkably reduced.

In order to solve the above-mentioned disadvantage, it is conceivable to coat the bonding wire 16 with a resin having a low gloss.

However, in the recent miniaturized light emitting element array chip 13, the light emitting elements 14 and the electrode terminals 15 are arranged close to each other. When the portion scatters or flows and adheres to the light emitting element 14, the light is blocked by the adhered resin, and as a result, the intensity of the light applied to the photoconductor is insufficient and the image is unclear. Disadvantages are induced.

[0007]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned drawbacks, and a method of manufacturing an optical printer head according to the present invention comprises the steps of: providing a circuit board on which a plurality of circuit wirings are attached; Mounting a light emitting element array chip having a plurality of light emitting elements and electrode terminals on the upper surface, and connecting the circuit wiring and the corresponding electrode terminals by bonding wires;
The surface of the light emitting element is coated with a hydrophilic resin, and thereafter,
A step of coating the bonding wire with a hydrophobic resin having a light reflectance of 10% or less, and a step of exposing the light emitting element by dissolving and removing the hydrophilic resin in water;
It is characterized by including.

Further, according to a method of manufacturing an optical printer head of the present invention, a circuit board on which a plurality of circuit wirings are attached is provided.
Mounting a light-emitting element array chip having a plurality of light-emitting elements and electrode terminals on the upper surface, connecting the circuit wiring and the corresponding electrode terminals by bonding wires, and setting the light-emitting element surface to have a light transmittance of 80% or more. And then coating the bonding wire with a hydrophobic resin having a light reflectance of 10% or less.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view of an optical printer head manufactured by the manufacturing method of the present invention.
Is a circuit wiring, 4 is a light emitting element array chip, 5 is a light emitting element, 6 is an electrode terminal, 7 is a bonding wire, and 8 is a hydrophobic resin.

The circuit board 1 has a structure in which a plurality of circuit wirings 3 are adhered on an upper surface of an insulating substrate 2 in a predetermined pattern.

The insulating substrate 2 is made of an electrically insulating material such as glass or glass cloth epoxy resin or paper phenol resin, and has a support mother for supporting a plurality of circuit wirings 3 and a light emitting element array chip 4 on its upper surface. Functions as a material.

When the insulating substrate 2 is made of, for example, glass, it is manufactured by forming a plate having a predetermined thickness by a conventionally known floating method or the like, and cutting and processing the plate into a predetermined rectangular shape.

The circuit wiring 3 on the insulating substrate 2 is made of a metal such as gold, silver (Ag), aluminum, chromium (Cr), titanium (Ti), and the like. It acts as a power supply wiring for supplying power to the power supply.

The circuit wiring 3 is formed by printing and applying a conductive paste obtained by adding and mixing an appropriate organic solvent and a solvent to, for example, silver powder on the upper surface of the insulating substrate 2 by well-known screen printing or the like. By baking this at a high temperature, it is deposited and formed in a predetermined pattern.

The light emitting element array chip 4 is mounted on the upper surface of the circuit board 1 described above.

The light emitting element array chip 4 has a plurality of light emitting elements 5 linearly arranged on the upper surface thereof at a dot density of, for example, 600 dpi, and a plurality of electrode terminals 6 electrically connected to the element 5. Since the light-emitting element 5 is made of a GaAlAs-based or GaAsP-based light-emitting diode, when power is applied to the light-emitting element 5, the light-emitting element 5 emits light at a predetermined luminance.

The light emitting element array chip 4 is manufactured by employing a conventionally well-known half-wiring manufacturing technique.

The circuit wiring 3 and the electrode terminal 6 are connected by a bonding wire 7.

The bonding wire 7 is connected to the circuit wiring 3
And an electrode terminal 6 corresponding to the wiring 3 individually and electrically connected, for example, 15 μmφ to 150 μm.
It has a wire diameter of mφ and is made of a shiny metal such as gold or aluminum.

The bonding wire 7 is covered with a hydrophobic resin 8 having a light reflectance of 10% or less.

As the hydrophobic resin 8, a resin material such as an epoxy resin, an acrylic resin, a phenol resin, or a urea resin is used as a main component, and a pigment such as carbon black or phthalocyanine blue is contained therein in an amount of, for example, 1% by weight to 30%.
By adding and mixing about 1% by weight, the light reflectance becomes 1
A material adjusted to 0% or less is used.

For this reason, when a part of the light emitted from the light emitting element 5 hits the hydrophobic resin 8 covering the bonding wire 7 when the optical printer head is used, most of the light existing in the hydrophobic resin 8 Etc. and diffuse reflection hardly occurs. Therefore, the light irradiated to the photoconductor is only light corresponding to the image data, and a desired good image can be obtained by forming an accurate latent image on the photoconductor.

If the surface roughness of the hydrophobic resin 8 is set to 0.1 μm to 10.0 μm in terms of the center line average roughness Ra, a part of the light emitted from the light emitting element 5 is When the light impinges on the hydrophobic resin 8 that covers the surface, the light is scattered on the surface of the hydrophobic resin 8, so that the light hardly goes to the photoconductor side, so that an unnecessary latent image is not formed on the photoconductor. There is also an advantage that it can be reliably prevented.

The above-mentioned light reflectance of the hydrophobic resin 8 is not the reflectance for all the light, but is at least the above-mentioned condition (light reflectance of 10% or less) for the light of the light emitting element 5.
Anything that satisfies is acceptable. At this time, the color of the hydrophobic resin 8 is black or a color having a complementary color with the light of the light emitting element 5.

Thus, the optical printer head described above supplies power from the light emitting element 5 via the circuit wiring 3 and the electrode terminals 6 and the like.
To selectively cause the light emitting elements 5 to individually emit light based on image data, and irradiate and form the emitted light on a photosensitive member via a lens (not shown) to form a predetermined latent image on the photosensitive member. By doing so, it functions as an optical printer head. Then, the latent image formed on the photoconductor is
A toner image is formed through a development process, and a predetermined image is recorded on the recording paper by transferring and fixing the toner image on the recording paper.

Next, a method of manufacturing the above-described optical printer head will be described with reference to FIGS.

(1) First, as shown in FIG. 2A, a light emitting element having a plurality of light emitting elements 5 and electrode terminals 6 on a circuit board 1 on which a plurality of circuit wirings 3 are attached. The array chip 4 is mounted, and the circuit wiring 3 and the electrode terminal 6 corresponding to the wiring 3 are electrically connected.

The light emitting element array chip 4 is mounted on a predetermined area on the upper surface of a circuit board by, for example, a chip mounter or a die bonder, and an adhesive 10 such as epoxy resin is interposed between the chip 4 and the circuit board 1. By doing so, it is fixed at a predetermined position on the circuit board 1.

The electrical connection between the electrode terminals 6 of the light emitting element array chip 4 and the circuit wiring 3 is made by using a wire bonder, whereby the electrode terminals 6 and the circuit wiring 3 are electrically connected via the bonding wires 7. Connected.

(2) Next, as shown in FIG. 2B, the surface of the light emitting element 5 is covered with a hydrophilic resin 9.

The hydrophilic resin 9 is a resin material having a hydrophilic group such as a hydroxyl group (OH), a carboxyl group (COOH), an amino group (NH ₂ ), a ketone group (CO), a sulfo group (SO ₃ H). For example, it is made of polyvinyl alcohol, cellulose resin, or the like, and a precursor of these resins is applied to the light-emitting element 5 on the light-emitting element array chip using a dispenser or the like, and then heated and polymerized. The resin 9 is formed.

(3) Next, as shown in FIG. 2C, the bonding wire 7 is covered with a hydrophobic resin 8 having a light reflectance of 10% or less.

The hydrophobic resin 8 has a phenyl group (C ₆ H).
₅₎ and an alkyl group (C _n H _{2n + 1)} a resin material having a hydrophobic group such as, for example, an epoxy resin or an acrylic resin, a phenol resin, as a main component urea resin or the like, carbon black, phthalocyanine blue, etc. therein The pigment of
About 30% by weight, and applying such a resin precursor using a dispenser or the like so that the bonding wire 7 is completely covered, and then heating and polymerizing this at a high temperature. Thereby, the hydrophobic resin 8 is formed.

At this time, since the hydrophobic resin 8 has a large number of hydrophobic groups in its molecular structure and has poor wettability to the hydrophilic resin 9, a part of the hydrophobic resin 8 is scattered. The hydrophilic resin 9 can effectively prevent the colored hydrophobic resin 8 from adhering to the hydrophilic resin 9 on the light emitting element 5 even if the colored resin flows or flows. Can be.

The surface roughness of the hydrophobic resin 8 is, as described above, a center line average roughness Ra of 0.1 μm to 10.0 μm.
In order to obtain such a surface state, when forming the hydrophobic resin 8, the applied precursor is rapidly heated and thermally cured before the surface is leveled. Alternatively, there is a method of adding a predetermined amount of an inorganic filler to a precursor to be the hydrophobic resin 8 and distributing them in the vicinity of the surface of the hydrophobic resin 8.

(4) Finally, as shown in FIG. 2D, the hydrophilic resin 9 is removed from the light emitting element 5.

Since the hydrophilic resin 9 has a large number of hydrophilic groups in its molecular structure, it can be easily removed by washing with water or the like, whereby the light emitting element 5 on the upper surface of the light emitting element array chip can be removed. It is completely exposed, and the optical printer head as a product is completed.

In this case, as described above, since the hydrophobic resin 8 does not exist on the light emitting element 5 of the light emitting element array chip 4, the light emitting element 5 emits light when the optical printer head is used. The emitted light is not interrupted by the colored hydrophobic resin 8 at all. Therefore, when the optical printer head is used, much of the light emitted from the light emitting element 5 is irradiated on the photoreceptor to obtain an image obtained. I can make it clear.

The present invention is not limited to the above-described embodiment, and various changes and improvements can be made without departing from the gist of the present invention.

For example, in the above-described embodiment, the hydrophilic resin 9 is removed from the light emitting element 5 in the step (4). Instead, the hydrophilic resin 9 is left on the light emitting element 5 as it is. You can leave it on. In this case, as the hydrophilic resin 9, a transparent resin having a light transmittance of 80% or more,
For example, polyvinyl alcohol, ethyl cellulose, or the like containing almost no impurities is used. By using such a transparent resin, when the optical printer head is used, most of the light emitted from the light emitting element 5 is transmitted through the hydrophilic resin 9 and the photosensitive resin is exposed. The body can be irradiated. Here, the light transmittance of the hydrophilic resin 9 used here is not the transmittance for all the light, but one that satisfies the above condition (light transmittance of 80% or less) at least for the light of the light emitting element 5. I just want it.

In the above-described embodiment, if the circuit wiring 3 on the circuit board 1 is formed of a metal which is relatively easily corroded, such as silver, and its surface is blackened by oxidizing or sulfurizing, When using the optical printer head,
Even if a part of the light emitted from the light emitting element 5 hits the circuit wiring 3, the light is rarely reflected on the surface of the circuit wiring 3 and irradiates the photoconductor, and an unnecessary latent image is not formed on the photoconductor. There is also an advantage that formation can be prevented more reliably.

[0042]

According to the present invention, when the optical printer head is used, even if a part of the light emitted from the light emitting element hits the hydrophobic resin covering the bonding wire, most of the light is present in the hydrophobic resin. Absorbed by pigments and the like, diffuse reflection hardly occurs. Therefore, the light applied to the photoconductor is only light corresponding to the image data, and a good image can be obtained by forming an accurate latent image on the photoconductor.

Further, according to the present invention, when the bonding wire is coated with the hydrophobic resin, even if a part of the hydrophobic resin is scattered or flows, these may be favorably formed by the hydrophilic resin on the light emitting element. As a result, the colored hydrophobic resin does not remain on the light emitting element. Therefore, when the optical printer head is used, much of the light emitted from the light emitting element is irradiated on the photoconductor, and the obtained image can be sharpened.

[Brief description of the drawings]

FIG. 1 is a sectional view of an optical printer head manufactured by a manufacturing method of the present invention.

FIGS. 2A to 2D are cross-sectional views for each process for explaining the manufacturing method of the present invention.

FIG. 3 is a sectional view of a conventional optical printer head.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Circuit board, 3 ... Circuit wiring, 4 ... Light emitting element array chip, 5 ... Light emitting element, 6 ... Electrode terminal, 7 ... Bonding wire, 8 ... Hydrophobic Resin, 9 ... hydrophilic resin

Claims (2)

[Claims] 1. A light emitting element array chip having a plurality of light emitting elements and electrode terminals on an upper surface is mounted on a circuit board on which a plurality of circuit wirings are attached, and an electrode terminal corresponding to the circuit wirings is provided. Connecting with a bonding wire, covering the surface of the light emitting element with a hydrophilic resin, and then,
An optical printer, comprising: a step of coating the bonding wire with a hydrophobic resin having a light reflectance of 10% or less; and a step of exposing the light emitting element by dissolving and removing the hydrophilic resin in water. Head manufacturing method. 2. A light emitting element array chip having a plurality of light emitting elements and electrode terminals on an upper surface thereof is mounted on a circuit board on which a plurality of circuit wirings are attached, and an electrode terminal corresponding to the circuit wirings is provided. Connecting the surface of the light-emitting element with a transparent hydrophilic resin having a light transmittance of 80% or more, and then coating the bonding wire with a hydrophobic resin having a light reflectance of 10% or less. A method for manufacturing an optical printer head.